Inductive loop antenna



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INVENTOR June 1 1926.

S. DAVlDSE INDUCTIVE LOOP ANTENNA Filed May 17. 1923 2 Sheets-Sheet 1 HTTORIVEY June 1 1926. 1,586,657

S. DAVIDSE INDUCTIVE LOOP ANTENNA F'iled May 17, 1923 2 Sheets-Sheet 2 L v W). I l l 7" 1 fi Patented June 1 1926.

'uurrr. STATES PATENT] OFFICE.

I SOLOMON DAVIDS E, 0F WHEELING, WEST VIRGINIA.

INDUCTIVE LOOP ANTENNA.

Application filed. May 17, 1823. Serial No. 639,571. r

This invention relates to radio receiving apparatus and it has for its primary obtion;

Figure 2 is an end elevation of the same; Figure 3 is a fragmentary detail View of the .base portion of the invention, partly in broken section, illustrating the pivotal mounting of the antenna supporting frame; Figure 4k is afragmentary detail section illustrating the antenna adjusting means;

Figure 5 is a sectional elevation of the same, the section being taken on line 55, Fig. 4; and

Figure 6 is a horizontal section on line 66, Fig. 1.

Referring to said drawings, 1 indicates a stationary base which has a centrally located upright pivot-pin 2 upon which is mounted for rotary movement the base member 3 of a rotor embodying a frame which comprises a pair of upright posts 4 carried upon the opposite ends of said base 3, and a pair of horizontally disposed parallel bars 5' mounted upon and connecting the upper end portions of said posts at each of the two opposite sides of the latter.

The rotor frame 5 constitutes a support for the frame members of three separate loop antennae 6, 7 and 8 of a more or less common type, each antenna consisting of a length of bare copper wire 9 wound in a plurality of coils or loops upon its frame member. Each of said antenna frames comprises a pair of crossed arms 10 and 11, the arms 10 being disposed vertically between the two opposite pairs of bars 5, and the arms 11 being disposed horizontally and resting upon the lower bars 5 of each of said pairs. Each of said arms 10 and 11 carries a terminal piece 12 of fiber or other suit able insulating material upon which the antenna coils are wound, as shown.

The opposite ends of each loop antenna are attached to binding posts 13 and 1 1 car ried by the lowermost of the terminal pieces 12 and the antennae are wired in series, being' connected by suitable conductors 15, as shown in Fig. 1. A variable condenser 16 of forty three plates connected in parallel is mounted on the rotor base and has its ter-' minals connected by conductors 17 "to binding posts 18 and 19 carried in a strip 20 of fiber or other suitable insulating material provided on the rotor frame. Said binding posts 18 and 19 are, in turn, connected by conductors 21 to the binding posts 13 and 14, respectively, of the loop antennae 6 and 8.

The middle loop antenna 7 is preferably mounted stationarily on the rotor. frame, while each of the end antennae 6 and 8 are adjustable with respect to said antenna 7 being slidable upon the guide-like supportingbars 5. As herein shown for illustrative purposes, a micrometer screw 22 directed horizontally through each of the posts 41 has its inner end rotatably disposed in engagement with a clip 23 carried by the adjacent antenna frame. Manifestly, sliding adjustment of said end loop antennae toward and away from the middle loop antennae is effected by rotation of said screws 22.

In practice, an inductive field between loops .having a maximum width of ten inches has proved highly satisfactory. The micrometer adjustment described affords means for varying these mutual inductive fields to any extent required within the limits of their size for the, reception of different wave lengths. With the inductance of each loop antenna rated at about 600 microhenries, each is made a fundamental of approximately 260 meters capacity. Therefore, the range of reception may be varied from 260 meters to approximately 1000 meters, thus providing for high selectivity of wave lengths.

It will be noted that the apparatus described provides an extremely simple and effective inductive loop antenna for radio receiving and broadcasting apparatus, being adjustable for rendering such apparatus highly selective, distortionless and direc tional. And while I have described the structural features more or less specifically, it is to be understood that various mechanical changes may be made therein without departing from the spirit or scope of the invention as defined in the appended claims.

\Vhat is claimed is 1. An antennae including a main frame of substantially U-form, a pair of upper and a pair of spaced lower horizontal bars connected at their ends to opposite sides of the uprights of the frame, a series of antenna having cruci-form frames with :one of their arms horizontal and received in the space between the pairs of bars and held in position thereby, and screws threaded through the uprights and engaged with the horizontal arms of the adjacent antenna frames to horizontally adjust the latter.

2. An antennae including a main frame of substantially U-torm, a pair of upper and a pair of spaced lower horizontal bars connected at their ends to opposite sides of the uprights out the frame, a series of an tenna having cruci-form "frames with one of their ar-mshorizontal and received in the space between the pairs of bars and held in position thereby and means to relatively adjust the antenna frames on said .pairs of bars.

3. In an antennae, a base, a rotor disposed on the base, means to pivotally mount the rotor on the base, a series of antenna carried by the rotor each composed of a pair of arms in erucidform relation, a right angular insulating terminal carried by each of the ends of the arms, wire coiled about said terminals, an insulating mem'bea carried by the rotor, binding posts 'on the insulating member, binding posts on the ends of the terminals and flexible connections between the binding posts of the antenna and the binding posts of the insulating member.

t. In an antennae, a base, a U-shaped rotor disposed on the 'base and having a bottom formed with a widened part, means to pivo'ta'lly mount the bottom on the base, a series of antenna carried by the rotor between the vertical arms thereof, .an insulating member carried .by tliewidened part of the bottom, binding posts on the insulating member, .a condenser on the rotor bottom movable therewith, and flexible connections between the condenser, the binding posts and the antenna.

An antennae including a main frame, a pair of upper and a pair of spaced :lower horizontal 'bars connected to the tra n'ie, a series of antenna having eruci-lorm frames with one of their arms horizontal and received in the space between the pairs ot "bars and held in position thereby and means to relatively adjust the antenna frames on'said pairs of bars.

In testimony whereof, I-affiX my signature.

SOLOMON DAV'I'DSE. 

